In the first episode Kitty Trevelyan tries to put the troubles of her past behind her as she joins two other girls, Flora Marshall and Rosalie Berwick, to volunteer at one of the busiest war hospitals in Northern France.
Despite struggling with some personal problems, Kitty throws herself into her work, helping new patients Major Edward Crecy and Private Jackie Byeford. Crecy awakens from the brink of death but still badly wounded, to find his troops have been decimated. Traumatised by war, Crecy fears he will never be able to return to his old life.
Thomas wrestles with a growing attraction to Kitty, and Joan reveals a dark secret to one of her patients. While Thomas may not be making much headway with Kitty, he is having more success on the wards with a pioneering wound irrigation system.
Joan is in agony not knowing whether her fiancé is alive or dead. Joan's spirits are lifted by the arrival of thirteen Tommies from her home town of Liverpool - known as 'The Lucky 13'. Joan has a fondness for these men whose spirit has given them a belief that if they all stick together, none of them will die.
Grace finds herself threatened by Colonel Ballard, an aggressively rude and war-scarred commander of a Sikh regiment, while Joan still waits anxiously for news from her fiancé. It seems Colonel Ballard would rather be with his men than at rest within the calm sanctuary of the wards.
Joan is hauled up on a charge of aiding the enemy and faces a possible lifetime in prison, and her actions send ripples through the hospital. As night falls some rules will be broken, others upheld and as the war machine grinds on, faith, hope and love are put to the test.
Hermione Norris
Matron Grace Carter
Suranne Jones
Sister Joan Livesey
Oona Chaplin
Kitty Trevelyan
Kevin Doyle
Lt Col Roland Brett
Alice St. Clair
Flora Marshall